The use of coal derived fuels, particularly in the United States because of its vast coal resources, has become increasingly important as an alternative energy source. Unfortunately, the energy content of gaseous fuel derived from coal is considerably lower than that of natural gas. Approximately, 150 BTU of heat is in a cubic foot of gaseous fuel derived from coal by the Lurgi process as compared to 900 BTU of heat in a cubic foot of natural gas. In spite of the low energy content of gaseous fuel derived from coal (hereinafter referred to as "LBG fuel"), it is desirable to provide a gas turbine engine capable of utilizing LBG fuel. However, in a gas turbine electrical power generating system wherein the gas turbine engine is utilized to supply compressed air for producing LBG fuel from coal by the Lurgi process, there is no LBG fuel available to be burned in the gas turbine engine until it is produced in the gasification process. This necessitates that the gas turbine engine have the capability of burning, not only the LBG fuel, but another fuel, e.g. natural gas, for start-up purposes and until the system produces LBG fuel.
Heretofore, as exemplified in the following patents, gas turbine engines have been designed to have dual fuel burning capabilities:
U.S. Pat No. 3,991,561 Leto; Nov. 16, 1976; PA0 U.S. Pat. No. 3,766,734 Jones; Oct. 23, 1973; PA0 U.S. Pat. No. 3,517,679 Williamson; June 30, 1970; PA0 U.S. Pat. No. 3,139,724 Nerad et al; July 7, 1964; PA0 2,931,429 Brown; Apr. 5, 1960; PA0 U.S. Pat. No. 2,854,819 Walker; Oct. 7, 1958; PA0 U.S. Pat. No. 2,771,741 Barnard 4th; Nov. 27, 1956; PA0 British Pat. No. 723,110 Morley; Feb. 2, 1955.
However, in the heretofore known dual gas turbine engines, the combustor and fuel nozzles or burners are independently supported so that problems of alignment and thermal differential expansion, between the combustor burner nozzles and the engine casing, exist.
It is, therefore, an object of this invention to provide combustor and fuel burner assembly for a gas turbine engine in which the problems of differential expansion and contraction and alignment of components are obviated in a simple manner.
It is another object of the present invention to provide a combustor and fuel burner assembly for a gas turbine engine which is relatively simple in construction and at the same time provides for support of the combustor housing and relative movement between the combustor housing and the engine casing.
It is a further object of this invention to provide a fuel burner and combustor assembly which is relatively inexpensive, simple in construction and having increased reliability over heretofore known combustor assemblies for gas turbine engines.
A still further object of the present invention is to provide a combustor and fuel burner assembly having dual fuel burning capability where disassembly and reassembly of the fuel system to switch from liquid fuel to gaseous fuel is obviated; where quick change from one fuel to another is achievable without shutdown of the gas turbine engine and where the engine can operate over a wide range of speeds.